Sepsis-induced acute lung injury is still associated with high morbidity and mortality. The pathophysiology is complex, and markers of injury include increased extravascular lung water. To evaluate the effects of the novel dual endothelin receptor antagonist tezosentan on endotoxin-induced changes in extravascular lung water and gas exchange, 16 pigs were anaesthetized and catheterized. Twelve animals were subjected to 5 h of endotoxemia. After 2 h, six of these animals received a bolus of tezosentan 1 mg kg−1 followed by a continuous infusion of 1 mg kg−1 h−1 to the end of the experiment at 5 h. Conventional pulmonary and hemodynamic parameters were measured. Extravascular lung water was determined in these pigs after 5 h of endotoxemia, as well as in the four additional nonendotoxemic sham animals. Tezosentan in the current dosage counteracted the deterioration of lung function caused by endotoxin, as measured by dead space, venous admixture, and compliance. In addition, pulmonary hypertension was attenuated. Tezosentan had a marked effect on the endotoxin-induced increase in extravascular lung water that was reduced to levels observed in nonendotoxemic sham animals. These results suggest that endothelin is involved in endotoxin-induced lung injury and the development of pulmonary edema. Dual endothelin receptor antagonism may be of value in the treatment of sepsis-related acute lung injury.